1. Field of the Invention
The present invention is directed generally to an electromagnetic power relay, and more particularly to a relay having at least one stationary contact element and a movable contact element formed as a leaf spring clamped at one end. A magnetic system having an armature acting on the leaf spring through a slide which is movable generally perpendicular to the extent of the leaf spring displaces the leaf spring from its quiescent position to a working position.
2. Description of the Related Art
A power relay is disclosed in German Published Application 29 12 800 A1 which include a card-shaped slide for operating a contact spring. The slide has an end edge lying parallel to the surface of the contact spring that contacts and pushes against the broad side of a contact spring for actuating the middle contact spring. The contact spring is thus uniformly pivoted about its attachment location.
In power relays having contact springs, the leaf spring material which forms the contact springs must have an adequate cross section to be able to carry the switching current without unwanted overheating. One problem is that a larger spring cross section has a high spring modulus and, thus, is quite stiff. In order to actuate such a stiff spring, particularly a spring of a predetermined length, a larger magnetic system is required. Such larger magnetic system requires a corresponding increase in the switching current, which in turn requires an increase in the spring cross section so that the armature may reliably switch the spring. Therefore, the tendency is to increase the size of the relay as well as the current consumed thereby.
It is universally desired to miniaturized power relays. However, there are limits on miniaturization imposed by the enlargement of the magnetic system and the increase in the spring lengths for the reasons just described.